JPH072700U - Cryogenic tank membrane fold structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a membrane pleated structure for a low temperature tank which prevents plastic deformation by relatively easy means and has high strength reliability. [Structure] In a membrane structure attached to the inside of a tank for storing low-temperature liquid, it has a bulging protrusion projecting near the center of the height of the fold and extending relatively long in the height direction of the cross section of the fold. In addition, it has a spherical bulging protrusion having a circular arc-shaped cross-section protruding from the center of the height of the fold.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pleated structure of a membrane attached to the inner wall of a tank that stores a low temperature liquid.

[0002]

[Prior art]

 In a tank that stores a cryogenic liquid such as liquefied gas, as shown in the inner perspective view of FIG. 3A and the enlarged view of FIG. 3B, the inside of a concrete skeleton 6 made in a vertical cylinder shape. A cold insulating material 9 is attached to the inner surface of which a stainless steel membrane is fixed by an anchor 4. The membrane is composed of the flat plate portion 3 and the folds 2, and is in direct contact with the low temperature liquid 7. In this type of tank, the pleats 2 are closed when the membrane is not in contact with the low temperature liquid 7 as shown in FIG. 4 (A) when the liquid is empty. However, when the liquid is filled, the flat plate portion 3 contracts at a low temperature with the anchor 4 as a fixed point, as shown in FIG. As a result, the lower end of the pleat 2 is opened so that an excessive tensile load is not applied to the anchor 4 and the flat plate portion 3. At that time, hydraulic pressure is also applied to the folds 2 and the flat plate portion 3. Conventionally, the folds 2 have a structure in which a flat plate is bent or two plates are welded at the top.

[0003]

[Problems to be solved by the device]

 In this way, the folds are arranged vertically and horizontally on the membrane to absorb the low-temperature shrinkage deformation. However, due to the increase in hydraulic pressure accompanying the recent enlargement of the storage tank, as shown in Fig. 5, the folds are placed inside the folds. The problem of plastic deformation has arisen. In order to prevent such deformation of the folds, it is conceivable to increase the membrane plate thickness to improve the strength, but this will lead to a significant increase in cost, making pressing difficult.

The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a membrane pleated structure for a low temperature tank which prevents plastic deformation by relatively easy means and has high strength reliability. To do.

[0005]

[Means for Solving the Problems]

 Therefore, in the invention of claim 1, in the membrane structure attached to the inside of the tank for storing the low temperature liquid, the membrane structure is projected near the height center of the fold and extends relatively long in the height direction of the cross section of the fold. It is characterized by having a bulging protrusion.

Further, in the invention of claim 2, in a membrane structure attached to the inside of a tank for storing a low temperature liquid, a spherical bulging protrusion projecting near the height center of the fold and having an arc-shaped cross section. It is characterized by having a part.

[0007]

[Action]

 According to this structure, the bulging protrusions provided on the folds increase the rigidity of the vertical plate portion of the folds, so that the proof strength against the out-of-plane load due to the hydraulic pressure is improved and the protrusion-free sub-projections are used. Plastic deformation is less likely to occur than the conventional shape, and strength reliability is increased.

[0008]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an embodiment in which the present invention is applied to a membrane at a corner portion between a side wall and a bottom plate of a cylindrical tank. A perspective view and the same figure (B) are the mesh division diagrams of the same figure (A).

In the above figure, 5 is a corner piece that connects the membrane fold on the side wall of the tank to the membrane fold on the bottom, and the flat portion 3 is bent by pressing to form the fold 2. In addition, a bulging protrusion 1 bulged outward by a press is provided at the center of the height of the vertical plate of the fold 2.

By the way, in the conventional corner piece, as shown in FIG. 3 (B), the membrane fold 2 does not have the protrusions 1 and is weak against the out-of-plane load due to the hydraulic pressure of the stored liquid. When used in a tank, there is a risk of plastic deformation due to hydraulic pressure.

However, in the structure of the present invention, as shown in FIGS. 1 (A) and 1 (B), the corner piece has the bulging projection 1 on the fold 2, and the out-of-plane rigidity is high, so that the corner piece is hard to be deformed. There is no fear of plastic deformation due to pressure, and it can be applied to deep tanks.

Further, FIG. 2 shows an example in which the present invention is applied to a general membrane portion such as a tank side portion and a bottom portion, and the rigidity of the vertical plate of the pleats 2 is increased and the strength thereof is improved.

In order to increase the rigidity of the pleats 2 and to improve the strength thereof, the bulging protrusion 1 is generally used in both the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. It is effective to use a bulging protrusion that is relatively long in the height direction at the center of the inverted U-shaped cross section of the fold 2. Here, the bulging protrusion can be provided on either the inner surface or the outer surface of the membrane.

Because of the rigidity of the folds as in the embodiment shown in FIG. 2, in addition to the X-shaped deformation of the folds of the inverted V-shaped cross section, as shown in FIG. That is, it may be important to increase the rigidity against X-shaped deformation in the ridge direction. Therefore, in the embodiment shown in FIG. 2, it is practical that the bulging protrusion has a substantially spherical shape with a relatively low height.

[0015]

[Effect of device]

 According to the structure of the present invention, even when a low temperature liquid such as liquefied natural gas is put in the low temperature liquid storage tank, the strength of the membrane pleats is not plastically deformed by the liquid pressure, and the strength reliability can be secured.

In short, according to the invention of claim 1, in the membrane structure attached inside the tank for storing the low temperature liquid, the ridge is provided so as to project near the center of the height of the folds and is compared in the height direction of the cross section of the fold. The present invention is extremely useful industrially because it has a bulging projection that extends for a long time to prevent plastic deformation by a relatively easy means and to obtain a membrane fold structure of a low temperature tank with high strength reliability. .

According to the invention of claim 2, in the membrane structure attached inside the tank for storing the low temperature liquid, the spherical bulging projection having a circular arc-shaped cross-section projecting near the center of the height of the folds. By having a section, it is possible to prevent plastic deformation with relatively easy means, and to prevent the plastic fold in the ridge direction of the folds, in addition to the membrane fold structure of the low temperature tank with high strength reliability. The device is extremely useful in industry.

[Brief description of drawings]

FIG. 1 shows a first embodiment in which the present invention is applied to a side wall of a cylindrical tank and a corner membrane of a bottom plate. FIG. 1A is a perspective view of the corner membrane, and FIG.
Is a mesh division diagram of FIG.

FIG. 2 is a perspective view showing a second embodiment in which the present invention is applied to a side wall membrane of a cylindrical tank.

3A and 3B show a conventional low temperature liquid storage tank, in which FIG. 3A is a vertical perspective view thereof, and FIG. 3B is an enlarged perspective view of a corner portion of FIG.

FIG. 4 shows the shape of the membrane of FIG. 3, FIG. 4 (A) shows the membrane shape when the liquid is empty, and FIG. 4 (B) is a perspective view showing the membrane shape and the load when the liquid is full.

FIG. 5 is a perspective view showing a state in which plastic deformation due to hydraulic pressure is generated in the folds in FIG. 4 (B).

[Explanation of symbols]

 1 Bulging protrusion 2 Membrane fold 3 Membrane flat plate 4 Anchor 5 Bottom corner piece 6 Concrete skeleton 7 Low temperature liquid 8 Roof 9 Cooling material

Claims (2)

[Scope of utility model registration request] 1. A membrane structure attached to the inside of a tank for storing low-temperature liquid, wherein a bulging projection portion is provided near the center of the height of the fold and extends relatively long in the height direction of the cross section of the fold. A low temperature tank membrane pleated structure characterized by having. 2. A membrane structure attached to the inside of a tank for storing low-temperature liquid, characterized in that it has a spherical swelling protrusion having a circular arc-shaped cross-section protruding near the center of the height of the folds. Membrane fold structure for low temperature tank.